1. Field of the Invention
The present invention relates to firearms and more particularly to trigger mechanisms for use in rifles and other manually actuable instruments.
2. Discussion of the Prior Art
Rifle marksmanship has been continuously developing over the last few hundred years, and now refinements in materials and manufacturing processes have made increasingly accurate aimed fire possible. These refinements have made previously ignored ergonomic or human factors more significant as sources of error.
The term “rifle” as used here, means a projectile controlling instrument or weapon configured to aim and propel or shoot a projectile, and triggers or firearm actuator systems are discussed principally with reference to their use on rifles and embodied in mechanisms commonly known as trigger assemblies. It will become apparent, however, that trigger mechanisms for manually actuable instruments may include devices other than rifles, and may be used on instruments or weapons other than rifles which are capable of controlling and propelling projectiles (e.g., rail guns or cannon). The prior art provides a richly detailed library documenting the process of improving the ergonomics of actuating rifles and other firearms (e.g., as shown in FIG. 1) and other manually actuable instruments.
Modern firearms such as rifles make use of cartridges that include a projectile seated in a casing. The casing has an internal cavity defined therein that contains a charge of rapidly combusting powder. A primer is seated in a recess formed in a rear portion of the casing. A hole in the primer casing places the primer in communication with the internal cavity containing the power. A projectile is seated in the front portion of the casing such that the powder is more or less sealingly contained in the casing between the primer and the projectile.
An action, such as a bolt action, is used to fire the cartridge. For example, the action can include a striker that carriers a firing pin. The striker can be coupled to a biasing member, such as a spring. The spring provides a motive force for the striking to cause the firing pin to impact the primer. More specifically, the spring can be compressed, or cocked, by drawing the striker rearwardly. Engagement between a sear and the striker can maintain the striker in a cocked position.
The action can then be used to advance the cartridge into a firing chamber ahead of firing. While in the firing chamber, a trigger mechanism can be used to release the sear to cause the firing pin to strike the primer, causing the primer to ignite. The ignition is directed to the powder, which burns within the casing. The powder burns within the casing to generate a rapidly expanding gas, which propels the projectile out of the casing and through the barrel.
Safety mechanisms are often used in the trigger mechanism to selectively control whether the trigger mechanism may release the sear. However, safety mechanisms may interfere with trigger feel, trigger pull or other factors which directly and adversely affect the shooter's ability to precisely control trigger actuation.
When firing a shot, a trained shooter will carefully control breathing motions, check sight alignment as part of the continuous aiming process, and then carefully squeeze the trigger to “break” the shot at a moment which is chosen by the shooter to maximize the likelihood of a “hit” on the target. The shooter's ability to repeatably and precisely execute this planned sequence of steps is determined in part by the trigger assembly's ergonomics and consistent, repeatable operation. Bad triggers exhibit uneven response to trigger finger pressure (or “creep”) and do not actuate or “break” cleanly and consistently. Often, a marksman or precision shooter will struggle to adjust the performance on a trigger to maximize that specific shooter's ability to precisely control trigger actuation or “break”.
Traditional rifle triggers have been categorized as single stage triggers or two stage triggers. Two-stage triggers are often used on military weapons. As the name implies, the trigger take-up is in two stages. The first stage is usually about ¼″ of lighter “slack”, before the second stage trigger pull begins, which ends with the trigger break. There is a difference in the weight of the trigger pull between the two stages which can be easily felt, where the first stage travel is light and the second stage requires notably greater force. A single-stage trigger does not typically have nearly as much travel as a two-stage trigger, so the shooter simply applies trigger pressure or force until the trigger breaks. Single stage triggers are more often used on sporting rifles.
Product liability lawsuits have exacerbated the shooter's ergonomics problems by forcing most manufacturers to design trigger assemblies which are nearly impossible for the shooter or user to tune or adjust. Some shooters will replace the entire trigger assembly in a rifle having a “lawyer's trigger” in the hopes of improving trigger adjustability.
There is a need, therefore, for a drop-in trigger assembly which can be used to enhance the ergonomics of trigger actuation and allow the shooter or user to tune or customize the trigger for his or her needs.
The subject matter claimed herein is not limited to embodiments that solve any of the cited disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some examples described herein may be practiced.